Instructables
Have you ever had a rubber band powered balsa wood aircraft? I did, and i was mad when it broke. So i came up the the Portable Propeller Engine, I call it the Porta-Prop.

It is a self supporting rubber band powered engine shaft and blade. It is designed to fit a specific type of balsawood aircraft sold at Michael's craft store, but im sure it will fit any old thing you strap it to. Now you can play with the r-band powered craft as much as you want, and when it breaks, you can simply switch the prop over to a new plane! Here's how to make it....

Materials:

1 proconstructed balsa wood airplane (I got mine from MIchael's crafts for $1)

1 long and one small rubberband

1 or 2 Lego propellers (the bigger the better)

a small paperclip

less than a foot of 1/4" dowel rod (use poplar or pine)

certain common Legos, pictured below

Tools:

a ruler

a dremel tool or something with simiar drilling and sanding capabilities

superglue

needlenose pliers

silicone spray makes it much faster

remove the nose weight
 
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Step 1: Making the rotary shaft

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It is pretty hard to give a good verbal description of what a lego looks like, so there are ample picture given.

1. get out your long rubberband and the three other legos pictured. A black ridged rod about an inch long, a gray friction nut, and a cylindrical hollow uni-bumb.

2. cut your rubberband and slide the ends through the top of the black uni-bumb.

3. slide the black uni-bump with the band in it onto the black ridged rod in such a way that the rubberband is also attached to the rod. Slide the gray friction nut onto the shaft, and put superglue between the nut and black uni-bump to help permanently attach these items to the black ridged rod.

4. (note in the photo i used a cylindrical unibump for this part, you should use two cubic unibumps)
get two cubic uni-bumps. you can lego lock them and glue them together to that the holes are facing the same direction.

5. Now get your propellors ready, and assemble the whole thing as shown in the first photo.
lukeD4 years ago
i'v got a tip:
make better (cleaner) pictures.

but i like the instuctable!!!
hassaan.4 years ago
MechEngineerMike,
                          Hi,man i need serious help frm u, i have been given a project on making a glider plane which are not operated by any set of batteries or fuel allowed to use small pastic propellers on their planes.And i couldn't get to know frm ur presentation how to build a propeller?? ... plz help
:)
MechEngineerMike (author)  hassaan.4 years ago
Do you mean the blades themselves? On my little plane, those were legos. They are ideal because they are lightweight, strong, and seamless, and because it would be hard to make your own propellers.  The rest of the model is simply attaching one end of the rubber-band to the prop axle and the other end to a fixed point of the plane.  Hope that helps.

By the way, It would also be helpful if your message did not have spelling errors, for future reference.
Mike
Colonel885 years ago
Good job, but sheet pics... Hard to understand, no offense
platinum975 years ago
Do I have to use a propeller, can't I make one out of cardboard or sumthin, cuz I don't have time to buy one. Cuz with my friends we all make one of these instructables people make, then have fun with the things we make. So is there I way I can make a simple propeller out of household items
MechEngineerMike (author)  platinum975 years ago
well my advise is that it would save more time to buy one somewhere, check your local stores for lego packs that have propellors or a hobby shop. IF you really wanted to make one, keep in mind, it should be as symetrical as possible to avoid misalignment of weight problems. I would suggest making a model of the propellor out of modeling clay, bake it to harden it. Then stick your model into some JB stick weld or Mighty Putty to make a mold. Then when the mold hardens, use more mighty putty with the mold and make a propellor, you can always sand down imperfections later too. but all that is very involved...
Thank you!! I wanted to make one actually! Thanks for the advice, I'm off to make the plane!
ktalex5 years ago
hahah lol i saw this on the berenstein bears.
SeanOTheDed5 years ago
I know it is good to encourage people, but there are some glaring issues here with me. So, please take this as some constructive criticism please. The pictures are easy to fix really. Most camera buttons on the digital cameras are actually 2 buttons in one. Most will focus and lock on half a push, then snap the photo on the full push. Take advantage of this by holding your hand flat at about the distance the object is away. Half press and hold the shutter button to focus on your hand, then swap your hand with the object and snap the photo. Also most cameras have a "close up" mode. Look for a flower symbol or something. My main issue is this setup will not fly any different than if you glued a weight to the nose. If you use Legos it will be too heavy and accelerate rapidly into the dirt. Lego props are heavy, not cheap, and they are designed for play, not practicality. I just don't want to see a kid glue all his precious legos together, just for it not to work. Make sure to use the propeller the plane came with or another hobby/light weight one. You might need to modify it though. I love legos and I've been building things that fly for over 2 decades. So that little issue hit a soft spot with me. ; ) Other than that, the format was pretty rock star : ) . Keep up the good work and we look forward to seeing more!
sharlston5 years ago
i do this with moddle cars aswell
j79jon5 years ago
From a private real plane flyer...good to go.
MechEngineerMike (author) 5 years ago
i found this website where you can buy a balsawood airplane that comes with a GREAT propeller for cheap.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK549

and haha, i think a good photographer could take great photos with my camera, but i am not a good photographer.
LOL !!! I was a terrible 'ible photographer. Blurry, badly framed, you name it. Finally I started propping my cheapo camera on a bag of beans and some books. And using the self-timer - that is key I think. Anyway I can see your pictures just fine and the explanations are clear.
lol...no offense
iectyx3c5 years ago
You've got my vote. Nice job and good explanations.
dunnos5 years ago
darn, I just came up with this but you already did it. only i was going to add the whole "build a plane from scratch" business
dallyspot5 years ago
Great instructable! But dude, get a better camera
rimar20005 years ago
Very good idea.
MLROD rimar20005 years ago
Does it work?
MechEngineerMike (author)  MLROD5 years ago
yea, you just have to wind it up a lot. If you dont wind it enough it rewinds itself and starts spinning the otherway! wich creates a cool nosedive. It creates a totally different flight pattern when it is powering itself. Once ive thrown it and the propeller flew off after flying a few feet, and it actually made the plane fly farther! perhaps thats a thought for a future project.
rimar2000 MLROD5 years ago
I suppose yes, I don't see any reason to not work.
MechEngineerMike (author) 5 years ago
yea if you have to buy all the legos from kits, those are expensive. But id like to think that most people (men at least) were legomaniacs at one time or another. They were easy for me to find. And as for the portion of dowel rod, portion of rubberband, and portion of paperclip.... i'd say the entire cost of the project was < $2.50 (including 1 plane) and 1 hour
weel by the time you buy all the parts you could buy 4 or five airplanes